PONTIAC, Mich. — Prosecutors in the criminal trial of James Crumbley, the father of Michigan school shooter Ethan Crumbley, opened their case Thursday by showing jurors an image of the gun’s unused cable lock still in its original packaging — teasing out evidence meant to suggest he failed to prevent the looming rampage.

“That nightmare was preventable and it was foreseeable,” Oakland County prosecutor Marc Keast said of the shooting spree at Oxford High School in November 2021 that left four dead and several wounded.

“There is no claim that James Crumbley gave his son that firearm knowing he would murder four students,” Keast added. “The question becomes how is it a father can be held responsible for the intentional acts of his teenage son?”

“It takes gross negligence, it takes causation of death and it takes the other person’s actions reasonably foreseeable — those are the three elements that must be proven,” he told the jury in a trial that could last about two weeks.

But in her opening statement, James Crumbley’s lawyer defended his actions in the months leading up to and on the day of the shooting, telling jurors that he was simply unaware of his son’s planned attack.

“You will not hear that James probably even suspected that his son was a danger,” Mariell Lehman said.

“What the prosecution wants you to believe, the part that’s not true, is that James Crumbley knew what his son was going to do and knew he had a duty to protect other people from his son,” she added. “Ladies and gentlemen, that’s not true. He didn’t know.”

Crumbley, 47, faces four counts of involuntary manslaughter, each representing one of the victims in the massacre at Oxford High School in suburban Detroit days after Thanksgiving.

His wife, Jennifer Crumbley, 45, was found guilty on the same charges last month and will be sentenced in April.

The prosecution and defense’s opening statements on Thursday walked jurors through similar presentations to those in Jennifer Crumbley’s landmark trial — the first time in the U.S. that a parent was held partially responsible for their child’s school shooting rampage.

Prosecutors said James Crumbley had bought Ethan a 9 mm Sig Sauer as a gift, at a time in his son’s life when he was struggling emotionally because his best friend had moved away.

“The decision that James Crumbley made to buy that gun as a gift for his son was made even though he knew that his son was in the midst of total and complete social isolation and had been in a downward spiral of distress that had been going on for some time,” Keast told jurors.

He went on to say Crumbley had further opportunities to prevent the violence, including by properly locking the weapon and by telling school staff he was aware his child had access to a firearm when he and his wife were warned the morning of the shooting about a drawing of a gun and a person shot on Ethan’s math homework.

But Lehman told the jury that Crumbley, a Door Dash driver, didn’t do anything differently on the day of the shooting because he was oblivious.

“When you’re not aware of an imminent, immediate danger, why would you do anything different than you’d normally do?” Lehman said. “You wouldn’t because you wouldn’t have any reason to.”

James Crumbley, dressed in a suit and glasses, mostly stared straight ahead, using an over-the-ear device to help with his hearing.

His wife’s trial was marked by emotional testimony, with video and photos of the shooting shown to jurors, and Jennifer Crumbley at times audibly sobbing in her seat. She took the stand in her own defense, testifying that she left control over storing and locking up the family’s firearms to her husband.

Opening statements in James Crumbley’s trial came after two days of jury selection in which 15 people were seated, 12 of whom will be randomly chosen to deliberate the verdict.

Similar to Jennifer Crumbley’s trial, the jury in James Crumbley’s trial is not being sequestered, but they are being asked to avoid watching or reading any news about the trial. In addition, the majority of jurors in his trial are also parents and are either gun owners, grew up around guns or have family or friends who have them — highlighting how firearm exposure is a familiar facet of this region of Michigan, where hunting is a popular activity.

Themes of parental responsibility and safe gun storage will hang over James Crumbley’s trial as well.

But there are some differences. At least two new witnesses are set to testify: the original owner of the 9 mm semi-automatic handgun, who sold the weapon and a cable lock to a gun store where James Crumbley bought it, and a student who was injured in the shooting.

Some evidence will also be new or withheld compared with the first trial. For instance, text messages between Jennifer Crumbley and her son that were shared while she and her husband were riding horses won’t be heard this time; the texts bolstered the prosecution’s case to show that Jennifer Crumbley was a negligent mother while her son was in distress and complained that there were demons in the family’s home. Oakland County Circuit Court Judge Cheryl Matthews on Thursday ruled the texts were inadmissible because there’s no evidence that James Crumbley was aware of them.

Matthews had emphasized during jury selection that James Crumbley’s case is separate from his wife’s, with different evidence, and asked if anyone’s judgment was so clouded from the media coverage that they could not be impartial.

“Are you able to set aside any sympathy that you feel and decide this case based on the evidence and the facts?” Matthews asked.

As with Jennifer Crumbley’s trial, son Ethan won’t be testifying in his father’s case.

Ethan, now 17, pleaded guilty in 2022 as an adult to murder, terrorism and other crimes and was sentenced in December to life in prison without parole.

Loved ones of some of the four shooting victims — Madisyn Baldwin, 17; Tate Myre, 16; Hana St. Juliana, 14; and Justin Shilling, 17 — attended Thursday’s opening statements.

It’s unclear if James Crumbley will take the stand. If found guilty, he faces up to 15 years in prison per count.

Among the first witnesses on Thursday was an Oxford High School teacher who was shot.

Selina Guevara reported from Pontiac and Erik Ortiz from New York.

This article was originally published on NBCNews.com